Acid-resisting article and method of making same



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UNITED STATES PATENT OFFICE.

JALVAHFW. CLEMENT, or CLEVELAND, omo, ASSIGNOR To THE CLEVELAND BRA'SS-MANUFAQTURING COMPANYyOF CLEVELAND, 0310; A CORPORATION, on 01310.

ACID-RESISTING ARTICLE AND METHOD OF MAKING; SAME.

Application filed July 26,

; To all whom it may 0001' Gem Be it known that I, ALVAH CLEMENT, acitizen ofv the United States, residing at- Cleveland,,in the county ofCuyahoga and State of Ohio, have invented a certain new and useful Imarovement in Acid-Resisting Articles and ethods of Making Samefof whichthe following is a full, clear, and

exact description.

This invention has to do with a method by which a metal alloy fabricatedinto suitable forms, may be prepared'so as to ef-,

fectivelyresist the action of sulfuric acid in all its forms,particularly hot dilute sulfuric acidpm A Experience reveals the factthat an alloy of iron and chromium in which alloy-carbon is present, ascarbids of iron and chromium, is in certain proportlons highlyreslst-ant to the actlon of sulfuric acid in 1ts various forms.

However, the, resence of any considerable iron and chromium in the alloyrenders the metallic alloyhard to fabricate and difiicult to machine.Furthermore, such an alloy tends toward brittleness, which, of course,is objectionable particularly where the alloy is made up intopumps,pipes and cocks and similar articles which enter into the making of apiping system through which the sulfuric acid may be caused to flow.

This invention therefore proposes a method for obtaining in the ultimatearticle the presence of iron and chromium carbid at those parts orsurfaces of the article which encounter the acid, and which thereforeshould exhibit the properties of resistance to the acid.

In proceeding with this method I form an alloy of iron and chromium ofthe desired proportions which generally may be sisting.

Specification of Letters Patent. Patented A 26 1 921:

1917. 'Serial No. 182,913.

be directly quenched in oil, water or other sultable quenching medium,or otherwise quickly cooled, which induces in the body at the surfacethus treated, an impregnation or coating which contains a highamount ofcarbon in the form of carbids of iron an chromium. y

The surfade thus treated will, therefore,

be "ery highly resistant to sulfuric or hydrochloric acid inconcentrated or dilute form,

and whether the acid is in hot or cooled condition.

The entire body of the article itself need not necessarily beimpregnated with carbon, as the only necessary thing, is to treat thesurface which is to be exposed. However, it will, of course, be apparentthat if the body of, the article itself absorbs more or less carbonduring the heat treating process it will not be objectionable, so longas the surface which will be contacted by the acid,

is made sufiiciently resistant by the method before disclosed.

Having claim isf 1. The method iron chromium alloy to have an acidresisting surface which consists in making an iron chromium alloy of thedesired proportions which alloy is substantially carbonless, thenfabricating the alloy into the article it is desired to make, treatingthe said article in suitable fashion to impregnate the surface, whichshould be acid resisting, with carbon, and quickly cooling the surfacewhich is to be acid resisting in any suitable manner, thereby to inducethe formation of iron and chromium ca-rbid in the body of thearticle atthe surfacegvhich is to be acid re- 2. As aILfiItIClG Of manufacturehaving describedmy invention, what of forming articles of an aILacid'resisting surface, said article comprising a body portion of analloy ofdesired ingredients, someor' all of which are I capable of formingcar'bids'whichare acid resisting, the said article at substantiallyonlythe surface which is to be acid resisting containing a largeproportion of carbids of the metals making up the alloy.

3. As an article of manufacture having an acid resisting surface whichconsists of a body formed of an alloy of metals of desired ingredients,some or all of which are capable of forming carbids which are acidresisting, that portion of the article which ity to, be exposed tocontact with the acid I being made resistant by the presence of carbidsof the metals forming the alloy assubstantially only the surfaceexposed.4:. As an article of manufacture having an acidresisting surface, a bodycomposed of an alloy 'of iron and chromium, the acid remy signature. I

\ ALVAH W. CLEMENT.

